It is well known in the art that anaerobic fermentation can be classified roughly into two classes: wet fermentation and dry fermentation. Wet anaerobic fermentation is widely used to produce biogas by means of the liquid waste materials, such as animal manure and yeast wash, etc. If wet anaerobic fermentation is used to produce biogas in cold regions, it consumes large amounts of energy, and thereby the economic benefit is less, even more, the loss is more than the gain.
In the past, dry anaerobic fermentation was mostly used in the brewing industry. But recently, study on the treatment of solid organic waste utilizing dry anaerobic fermentation is developing in China and abroad, which can help to produce organic fertilizer while obtaining clean energy (biogas). At the present stage, there are cylinder type and chamber type constructions. The cylinder type construction is difficult for loading and unloading materials and involves an extremely high cost. As for the chamber type construction, it is required to transport materials several times, that is, materials are at first pre-treated to raise temperature through aerobic fermentation, and then transported into the anaerobic fermentation chamber to produce biogas, after that, they go to the plant for producing organic fertilizer to be processed. The process by making use of the chamber type construction requires much labour and time. Also, the space for the chamber type construction is large, and the manufacturing accuracy of the sealing door of the anaerobic fermentation chamber and the demand for explosion-proof monitoring are both high.